1,1,3,3-tetramethylguanidine-gallane, (Me2N)(2)CN(H)center dot GaH3: an unusually strongly bound gallane adduct

The novel adduct 1,1,3,3-tetramethylguanidine-gallane, (Me2N)(2)CN(H).GaH3, has been prepared by the reaction of [(Me2N)(2)CNH2]Cl-+(-) with LiGaH4 in Et2O solution. Its spectroscopic properties indicate a monomeric species with an unusually strong coordinate link between the imido function and GaH3, an inference confirmed by the crystal structure at 150 K which also reveals significant secondary interactions through non-classical N-H center dot center dot center dot H-Ga bridges. Despite the intrinsic strength of the Ga-N bond, however, vaporisation at ca. 310 K occurs with partial dissociation, and decomposition via more than one pathway proceeds at temperatures >330-350 K to give a variety of products, including the free base, Me2NH, H-2, and a novel gallium-nitrogen compound composed of a Ga4N4 cubane-like core bridged on three edges by -N{C(NMe2)(2)}GaH2-units.